Wound healing facts for kids

Hand abrasion

Approximate days since injury
0	3	17	30

When an organism is wounded, the tissue at the wound is damaged. Several of the more complex organisms can replace this damaged tissue with new tissue. This occurs in several steps, and is generally known as tissue healing, or wound healing..

In undamaged skin, the epidermis (surface layer) and dermis (deeper layer) form a protective barrier against the external environment. When the barrier is broken, biochemical events repair the damage. This process is divided into predictable phases: blood clotting (hemostasis), inflammation, tissue growth (proliferation), and tissue remodeling (maturation). Blood clotting may be seen as part of the inflammation stage instead of a separate stage.

In general, after the wound is fully healed, a scar will remain. Even after the scar has appeared remodelling proceses take place. It can take a very long time until this scar has reached its final form.

Sometimes complications from wound healing can occur. A common one is infections during the healing process, which will lead to more scars or larger ones.

Images for kids

Approximate times of the different phases of wound healing on a logarithmic scale, with faded intervals marking substantial variation, depending mainly on wound size and healing conditions, but image does not include major impairments that cause chronic wounds.
A scab covering a healing wound
A fluorescence micrograph of cells in Drosophila larvae healing after a puncture wound. The arrow points to cells that have fused to form syncytia, and the arrowheads point to cells that are oriented to face the wound.